<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div{
            width: 100px;
            height: 100px;
            background: red;
            margin: 100px;
        }
    </style>
</head>
<body>
        <!--
                margin                 外边距（标签与标签之间的距离）



                    margin的单一样式和margin的复合样式都与border和padding类似；


        -->
    <div>div1</div>
    <div>div2</div>
</body>
</html>